I am trying to display only one digit to the right of the decimal place unless that digit is a 0, then there would be no decimal place displayed. I am a beginner and I cannot use any complicated coding or conditional statements. This is my current code but it will not display any decimal places in any case.
#include<stdio.h>
#include<math.h>
#define PI 3.1415927
int main()
{
//Local Declarations
float radius;
float volume;
float SA;
float height;
int dec;
int Dec;
int dec1;
int dec2;
int Dec1;
int Dec2;
//Statements
printf("Enter the radius: ");
scanf("%f", &radius);
height = radius;
volume = PI * pow( radius, 2.0) * height;
SA = (2.0 * PI * pow( radius, 2.0)) + (2.0 * PI * radius * height);
dec = (volume - (int)volume) * 10.0;
dec1= 0.1 * (int)dec;
dec2 = (dec1 + 2) % (dec1 + 1);
Dec = (SA - (int)SA) * 10.0;
Dec1 = 0.1 * (int)Dec;
Dec2 = (Dec1 + 2) % (Dec1 + 1);
//Output
printf("\n-=-=-=-=-=-=-=-=-=-=-=-=-=-=");
printf("\nVolume: %.*f\n",dec2, volume);
printf("Surface Area: %.*f\n",Dec2, SA);
printf("-=-=-=-=-=-=-=-=-=-=-=-=-=-=");
return 0;
} //main
You are declaring your dec variables as integers. You should use float instead. Any operation cast to an integer will result in the loss of the decimal.
Related
I'm writing a lighting system for 2D games using a rather common method of 2D radiosity. The idea is to generate a JFA voronoi of the game scene (black, alpha = 1.0 for occluders and color, alpha = 1.0 for emitters) and generate an SDF from the JFA. Next you raymarch every pixel on screen for N rays with M max steps on the SDF with random angle offsets for each pixel. You then sample the emitter/occluder surface at the end point of each ray, step back into empty space and sample again for light emitted in the nearest empty space. This gives you a nice result as seen below:
That isn't the problem, it works great. The problem is efficiency. The idea behind fixing this is to render the GI at 1/N sample size (width/N, height/N) and then upscale the GI using interpolation. As I've done below:
This is the problem. The upscaling I've accomplished using weighted color-interpolation, but it produces these nasty results near occluders:
Here's the full shader:
The uniforms passed are the GI downsampled texture (in_GIField), Scene (emitters/occluders only) Texture (gm_basetexture), Signed Distance Field (in_SDField), Resolution (in_Screen) and the Downsample ratio (in_Sample).
/*
UPSCALING SHADER:
Find the nearest 4 boundign samples to the current pixel (xyDelta & xyShift)
Calculate all of the sample's weights based on whether they're marchable or source pixels.
Final perform a composite weighted interpolation for the current pixel to the nearest 4 samples.
*/
varying vec2 in_Coord;
uniform float in_Sample;
uniform vec2 in_Screen;
uniform sampler2D in_GIField;
uniform sampler2D in_SDField;
#define TPI 9.4247779607693797153879301498385
#define PI 3.1415926535897932384626433832795
#define TAU 6.2831853071795864769252867665590
#define EPSILON 0.001 // floating point precision check
#define dot(f) dot(f,f) // shorthand dot of a single float
float ATAN2(float yy, float xx) { return mod(atan(yy, xx), TAU); }
float DIRECT(vec2 v1, vec2 v2) { vec2 v3 = v2 - v1; return ATAN2(-v3.y, v3.x); }
float DIFFERENCE(float src, float dst) { return mod(dst - src + TPI, TAU) - PI; }
float V2_F16(vec2 v) { return v.x + (v.y / 255.0); }
float VMAX(vec3 v) { return max(v.r, max(v.g, v.b)); }
vec2 SAMPLEXY(vec2 xycoord) { return (floor(xycoord / in_Sample) * in_Sample) + (in_Sample*0.5); }
vec3 TONEMAP(vec3 color, float dist) { return color * (1.0 / (1.0 + dot(dist / min(in_Screen.x, in_Screen.y)))); }
float TESTMARCH(vec2 pix, vec2 end) {
float aspect = in_Screen.x / in_Screen.y,
dst = distance(pix, end);
vec2 dir = normalize((end*in_Screen) - (pix*in_Screen)) / in_Screen;
for(float i = 0.0; i < in_Sample; i += 1.0) {
vec2 test = vec2(pix.x * aspect, pix.y) + (dir * (i/in_Screen));
test.x /= aspect;
vec4 sourceCol = texture2D(gm_BaseTexture, test);
float source = max(sourceCol.r, max(sourceCol.g, sourceCol.b));
if (source < EPSILON && sourceCol.a > 0.0) return 0.0;
}
return 1.0;
}
vec3 WCOMPOSITE(vec3 colors[4], float weights[4], vec2 uv) {
// (uv * A * B) + (B * (1.0 - A)) //0, 2, 1, 3
float weightA = (uv.y * weights[0] * weights[2]) + (weights[2] * (1.0 - weights[0])),
weightB = (uv.y * weights[1] * weights[3]) + (weights[3] * (1.0 - weights[1]));
vec3 colorA = mix(colors[0], colors[2], weightA),
colorB = mix(colors[1], colors[3], weightB);
return mix(colorA, colorB, uv.x);
}
void main() {
vec2 xyCoord = in_Coord * in_Screen;
vec2 xyLight = SAMPLEXY(xyCoord);
vec2 xyDelta = sign(sign(xyCoord - xyLight) - 1.0);
vec2 xyShift[4];
xyShift[0] = vec2(0.,0.) + xyDelta;
xyShift[1] = vec2(1.,0.) + xyDelta;
xyShift[2] = vec2(0.,1.) + xyDelta;
xyShift[3] = vec2(1.,1.) + xyDelta;
vec2 xyField[4]; vec3 xyColor[4]; float notSource[4]; float xyWghts[4];
for(int i = 0; i < 4; i++) {
xyField[i] = (xyLight + (xyShift[i] * in_Sample)) * (1.0/in_Screen);
xyColor[i] = texture2D(in_GIField, xyField[i]).rgb;
notSource[i] = 1.0 - sign(texture2D(gm_BaseTexture, xyField[i]).a);
xyWghts[i] = TESTMARCH(in_Coord, xyField[i]) * sign(VMAX(xyColor[i])) * notSource[i];
}
vec2 uvCoord = mod(xyCoord-xyLight, in_Sample) * (1.0/in_Sample);
vec3 xyFinal = WCOMPOSITE(xyColor, xyWghts, uvCoord);
vec4 xySource = texture2D(gm_BaseTexture, in_Coord);
float isSource = sign(xySource.a);
gl_FragColor = vec4((isSource * xySource.rgb) + ((1.0-isSource) * xyFinal), 1.0);
}
EDIT: This DOES produce the intended result in empty space, but ends up with nasty artifacting near emitters and occluders. I tried to solve this in the for-loop in the main function by weighting out the emitter/occluder (source pixels in the scene texture) colors, but this isn't working.
See shader code attached (Shadertoy). I noticed that the weighting function will actually produce some colors with a weight of 0 (as expected as originally written). I currently don't have a solution for how to remove colors from the interpolation process entirely.
Full Source Code
Full Color Shader Code
I found a code in geometry shader to calculate the derivatives of barycentrics w.r.t screen space coordinates (dudX,dudY,dvdX,dvdY)。
And here is the code:
void main()
{
// Plane equations for bary differentials.
float w0 = gl_in[0].gl_Position.w;
float w1 = gl_in[1].gl_Position.w;
float w2 = gl_in[2].gl_Position.w;
vec2 p0 = gl_in[0].gl_Position.xy / w0;
vec2 p1 = gl_in[1].gl_Position.xy / w1;
vec2 p2 = gl_in[2].gl_Position.xy / w2;
vec2 e0 = p0 - p2;
vec2 e1 = p1 - p2;
float a = e0.x*e1.y - e0.y*e1.x;
// Clamp area to an epsilon to avoid arbitrarily high bary differentials.
float eps = 1e-6f; // ~1 pixel in 1k x 1k image.
float ca = (abs(a) >= eps) ? a : (a < 0.f) ? -eps : eps; // Clamp with sign.
float ia = 1.f / ca; // Inverse area.
vec2 ascl = ia * vp_scale;
float dudx = e1.y * ascl.x;
float dudy = -e1.x * ascl.y;
float dvdx = -e0.y * ascl.x;
float dvdy = e0.x * ascl.y;
float duwdx = dudx / w0;
float dvwdx = dvdx / w1;
float duvdx = (dudx + dvdx) / w2;
float duwdy = dudy / w0;
float dvwdy = dvdy / w1;
float duvdy = (dudy + dvdy) / w2;
vec4 db0 = vec4(duvdx - dvwdx, duvdy - dvwdy, dvwdx, dvwdy);
vec4 db1 = vec4(duwdx, duwdy, duvdx - duwdx, duvdy - duwdy);
vec4 db2 = vec4(duwdx, duwdy, dvwdx, dvwdy);
int layer_id = v_layer[0];
int prim_id = gl_PrimitiveIDIn + v_offset[0];
gl_Layer = layer_id; gl_PrimitiveID = prim_id; gl_Position = vec4(gl_in[0].gl_Position.x, gl_in[0].gl_Position.y, gl_in[0].gl_Position.z, gl_in[0].gl_Position.w); var_uvzw = vec4(1.f, 0.f, gl_in[0].gl_Position.z, gl_in[0].gl_Position.w); var_db = db0; EmitVertex();
gl_Layer = layer_id; gl_PrimitiveID = prim_id; gl_Position = vec4(gl_in[1].gl_Position.x, gl_in[1].gl_Position.y, gl_in[1].gl_Position.z, gl_in[1].gl_Position.w); var_uvzw = vec4(0.f, 1.f, gl_in[1].gl_Position.z, gl_in[1].gl_Position.w); var_db = db1; EmitVertex();
gl_Layer = layer_id; gl_PrimitiveID = prim_id; gl_Position = vec4(gl_in[2].gl_Position.x, gl_in[2].gl_Position.y, gl_in[2].gl_Position.z, gl_in[2].gl_Position.w); var_uvzw = vec4(0.f, 0.f, gl_in[2].gl_Position.z, gl_in[2].gl_Position.w); var_db = db2; EmitVertex();
}
db0, db1 and db2 are the output derivatives of three vertex in a triangle.
vp_scale is a vec2 variable which contains (width, height) of display viewport.
I could understand the code until dudx, dudy, dvdx, dvdy.
The most confusion part for me is the db0, db1 and db2. Also, I dont know what duvdx and duvdy presents for.
I think maybe its something relate to perspective correction in rasterization-inpterpolation of vertex attribute. But I cant found a good way to the answer.
Does anyone have idea about it?
my result , but the shadow is so hard.
for (SceneLight* light : scene->lights)
{
Vector3D dir_to_light;
float dist_to_light;
float pdf;
int num_light_samples = light->is_delta_light() ? 1 : ns_area_light;
double scale = 1.0 / num_light_samples;
for (int i = 0; i < num_light_samples; i++) {
Spectrum light_L = light->sample_L(hit_p, &dir_to_light, &dist_to_light, &pdf);
Vector3D w_in = w2o * dir_to_light;
double cos_theta = std::max(0.0, w_in[2]);
Spectrum f = isect.bsdf->f(w_out, w_in);
Ray shadow_ray(hit_p + EPS_D * dir_to_light, dir_to_light, dist_to_light - (EPS_D * dir_to_light).norm(), 0);
if (!bvh->intersect(shadow_ray))
{
L_out += (f * light_L * (cos_theta * scale / pdf));
}
}
}
**
abolve is my some code and render result. The shadow looks so hard.If i want to make the shadow softer, What can I do? I am writing path tracing.
Thanks.**
I'm attempting to SLERP from GLSL (HLSL would also be okay as I'm targeting Unity3D)
I've found this page: http://www.geeks3d.com/20140205/glsl-simple-morph-target-animation-opengl-glslhacker-demo
It contains the following listing:
#version 150
in vec4 gxl3d_Position;
in vec4 gxl3d_Attrib0;
in vec4 gxl3d_Attrib1;
out vec4 Vertex_Color;
uniform mat4 gxl3d_ModelViewProjectionMatrix;
uniform float time;
vec4 Slerp(vec4 p0, vec4 p1, float t)
{
float dotp = dot(normalize(p0), normalize(p1));
if ((dotp > 0.9999) || (dotp<-0.9999))
{
if (t<=0.5)
return p0;
return p1;
}
float theta = acos(dotp * 3.14159/180.0);
vec4 P = ((p0*sin((1-t)*theta) + p1*sin(t*theta)) / sin(theta));
P.w = 1;
return P;
}
void main()
{
vec4 P = Slerp(gxl3d_Position, gxl3d_Attrib1, time);
gl_Position = gxl3d_ModelViewProjectionMatrix * P;
Vertex_Color = gxl3d_Attrib0;
}
The maths can be found on the Wikipedia page for SLERP: http://en.wikipedia.org/wiki/Slerp
But I question the line
float theta = acos(dotp * 3.14159/180.0);
That number is 2π/360, i.e. DEG2RAD
And dotp, a.k.a cos(theta) is not an angle
i.e. it doesn't make sense to DEG2RAD it.
Isn’t the bracketing wrong?
float DEG2RAD = 3.14159/180.0;
float theta_rad = acos(dotp) * DEG2RAD;
And even then I doubt acos() returns degrees.
Can anyone provide a correct implementation of SLERP in GLSL?
All that code seems fine. Just drop the " * 3.14159/180.0 " and let it be just:
float theta = acos(dotp);
I hope there will be an easy answer, as often times, something stripped out of Compact Framework has a way of being performed in a seemingly roundabout manner, but works just as well as the full framework (or can be made more efficient).
Simply put, I wish to be able to do a function similar to System.Drawing.Graphics.DrawArc(...) in Compact Framework 2.0.
It is for a UserControl's OnPaint override, where an arc is being drawn inside an ellipse I already filled.
Essentially (close pseudo code, please ignore imperfections in parameters):
FillEllipse(ellipseFillBrush, largeEllipseRegion);
DrawArc(arcPen, innerEllipseRegion, startAngle, endAngle); //not available in CF
I am only drawing arcs in 90 degree spaces, so the bottom right corner of the ellipse's arc, or the top left. If the answer for ANY angle is really roundabout, difficult, or inefficient, while there's an easy solution for just doing just a corner of an ellipse, I'm fine with the latter, though the former would help anyone else who has a similar question.
I use this code, then use FillPolygon or DrawPolygon with the output points:
private Point[] CreateArc(float StartAngle, float SweepAngle, int PointsInArc, int Radius, int xOffset, int yOffset, int LineWidth)
{
if(PointsInArc < 0)
PointsInArc = 0;
if(PointsInArc > 360)
PointsInArc = 360;
Point[] points = new Point[PointsInArc * 2];
int xo;
int yo;
int xi;
int yi;
float degs;
double rads;
for(int p = 0 ; p < PointsInArc ; p++)
{
degs = StartAngle + ((SweepAngle / PointsInArc) * p);
rads = (degs * (Math.PI / 180));
xo = (int)(Radius * Math.Sin(rads));
yo = (int)(Radius * Math.Cos(rads));
xi = (int)((Radius - LineWidth) * Math.Sin(rads));
yi = (int)((Radius - LineWidth) * Math.Cos(rads));
xo += (Radius + xOffset);
yo = Radius - yo + yOffset;
xi += (Radius + xOffset);
yi = Radius - yi + yOffset;
points[p] = new Point(xo, yo);
points[(PointsInArc * 2) - (p + 1)] = new Point(xi, yi);
}
return points;
}
I had this exactly this problem and me and my team solved that creating a extension method for compact framework graphics class;
I hope I could help someone, cuz I spent a lot of work to get this nice solution
Mauricio de Sousa Coelho
Embedded Software Engineer
public static class GraphicsExtension
{
// Implements the native Graphics.DrawArc as an extension
public static void DrawArc(this Graphics g, Pen pen, float x, float y, float width, float height, float startAngle, float sweepAngle)
{
//Configures the number of degrees for each line in the arc
int degreesForNewLine = 5;
//Calculates the number of points in the arc based on the degrees for new line configuration
int pointsInArc = Convert.ToInt32(Math.Ceiling(sweepAngle / degreesForNewLine)) + 1;
//Minimum points for an arc is 3
pointsInArc = pointsInArc < 3 ? 3 : pointsInArc;
float centerX = (x + width) / 2;
float centerY = (y + height) / 2;
Point previousPoint = GetEllipsePoint(x, y, width, height, startAngle);
//Floating point precision error occurs here
double angleStep = sweepAngle / pointsInArc;
Point nextPoint;
for (int i = 1; i < pointsInArc; i++)
{
//Increments angle and gets the ellipsis associated to the incremented angle
nextPoint = GetEllipsePoint(x, y, width, height, (float)(startAngle + angleStep * i));
//Connects the two points with a straight line
g.DrawLine(pen, previousPoint.X, previousPoint.Y, nextPoint.X, nextPoint.Y);
previousPoint = nextPoint;
}
//Garantees connection with the last point so that acumulated errors cannot
//cause discontinuities on the drawing
nextPoint = GetEllipsePoint(x, y, width, height, startAngle + sweepAngle);
g.DrawLine(pen, previousPoint.X, previousPoint.Y, nextPoint.X, nextPoint.Y);
}
// Retrieves a point of an ellipse with equation:
private static Point GetEllipsePoint(float x, float y, float width, float height, float angle)
{
return new Point(Convert.ToInt32(((Math.Cos(ToRadians(angle)) * width + 2 * x + width) / 2)), Convert.ToInt32(((Math.Sin(ToRadians(angle)) * height + 2 * y + height) / 2)));
}
// Converts an angle in degrees to the same angle in radians.
private static float ToRadians(float angleInDegrees)
{
return (float)(angleInDegrees * Math.PI / 180);
}
}
Following up from #ctacke's response, which created an arc-shaped polygon for a circle (height == width), I edited it further and created a function for creating a Point array for a curved line, as opposed to a polygon, and for any ellipse.
Note: StartAngle here is NOON position, 90 degrees is the 3 o'clock position, so StartAngle=0 and SweepAngle=90 makes an arc from noon to 3 o'clock position.
The original DrawArc method has the 3 o'clock as 0 degrees, and 90 degrees is the 6 o'clock position. Just a note in replacing DrawArc with CreateArc followed by DrawLines with the resulting Point[] array.
I'd play with this further to change that, but why break something that's working?
private Point[] CreateArc(float StartAngle, float SweepAngle, int PointsInArc, int ellipseWidth, int ellipseHeight, int xOffset, int yOffset)
{
if (PointsInArc < 0)
PointsInArc = 0;
if (PointsInArc > 360)
PointsInArc = 360;
Point[] points = new Point[PointsInArc];
int xo;
int yo;
float degs;
double rads;
//could have WidthRadius and HeightRadius be parameters, but easier
// for maintenance to have the diameters sent in instead, matching closer
// to DrawEllipse and similar methods
double radiusW = (double)ellipseWidth / 2.0;
double radiusH = (double)ellipseHeight / 2.0;
for (int p = 0; p < PointsInArc; p++)
{
degs = StartAngle + ((SweepAngle / PointsInArc) * p);
rads = (degs * (Math.PI / 180));
xo = (int)Math.Round(radiusW * Math.Sin(rads), 0);
yo = (int)Math.Round(radiusH * Math.Cos(rads), 0);
xo += (int)Math.Round(radiusW, 0) + xOffset;
yo = (int)Math.Round(radiusH, 0) - yo + yOffset;
points[p] = new Point(xo, yo);
}
return points;
}